1. Field of the Invention
The present invention relates generally to a switch structure design, and more particularly to an improved switch (cam) device in which a lead can be inserted and electrically connected. The switch device has a restriction body for guiding the carrier body. The switch device is applicable to both flat-head terminal lead and bare lead.
2. Description of the Related Art
A conventional switch or cam switch is applied to electrical engineering, electronic engineering and automatic control system for an operator to controllably switch on/off the console.
The conventional switch includes an insulation housing 10 generally made of plastic material. The housing 10 is formed with multiple cavities 11 in which a conductive metal member 20, a washer 30 assembled on the conductive metal member 20 and an adjustment screw 35 are mounted. In addition, the housing 10 is formed with multiple perforations 12 corresponding to the cavities 11 for the terminal leads to insert into the cavities 11. By means of operating the screw 35, the washer 30 is moved to press the terminal lead into electrical connection with the conductive metal member 20.
As shown in FIGS. 1 and 2, a rotary switch 13 and a cam 14 are disposed on the housing 10. When operating the rotary switch 13 to drive and rotate the cam 14, an operator can selectively controllably switch on/off every conductive metal member 20 mounted in the cavity 11. As known by those who are skilled in this field, multiple housings 10 can be stacked and plug-connected with each other to form multiple layers of housings 10. For example, as shown in FIG. 1, the housings 10 are stacked and assembled to form two layers of housings 10.
The conventional switch has a problem in structural design and application. That is, when multiple layers of housings 10 are applied to the automatic control system, the thickness or height of the housing 10 is limited within about 1 cm˜1.5 cm. Such limitation not only affects the operation space of the screw 35, but also leads to limitation of the form of the lead inserted in the cavity 11 for electrically connecting with the conductive metal member 20.
Please refer to FIGS. 2 and 3. In order to smoothly insert the terminal lead through the perforation 12 into the cavity 11 between the conductive metal member 20 and the washer 30, an operator will instinctively unscrew the screw 35. This often causes the screw 35 to drop out of the housing 10. For overcoming this problem of the conventional switch, when manufacturing the washer 30, the washer is punched and bent to form two arched wing sections 31 perpendicularly extending from the washer 30 for enclosing and restricting the screw 35 from dropping out of the housing 10 in operation. As known by those who are skilled in this field, this will complicate the structure of the washer 30 and increase the manufacturing cost of the washer 30. Moreover, in order to easily punch and bent the washer 30 to form the arched wing sections 31, the washer 30 must have a thin thickness (generally 0.6 mm). This lowers the structural strength of the washer 30 and deteriorates the ability to lock the terminal lead. This is not what we expect.
As aforesaid, when multiple layers of housings 10 are applied to the automatic control system, the thickness or height of the housing 10 is limited. This causes limitation of the operation space of the screw 35. As a result, the washer 30 is only applicable to the flat-head terminal lead such as O-type or Y-type terminal lead. With respect to the bare lead with larger diameter or thickness, it is hard to insert the bare lead into the cavity 11 between the conductive metal member 20 and the washer 30.
The conventional switch structure has some shortcomings in use and structural design that needs to be overcome. It is therefore tried by the applicant to provide an improved switch structure to eliminate the shortcomings existing in the conventional switch structure so as to improve the application and ensure the stability and lead locking ability of the switch structure. Under the limitation of the height of the housing, the switch structure of the present invention has an optimal structural strength and lead locking ability. Moreover, the switch structure of the present invention is simplified so that the manufacturing cost is lowered. In addition, the switch structure of the present invention is easily operable and applicable to both flat-head terminal lead (such as O-type or Y-type terminal lead) and bare lead.